The winter solstice marks the instant the sun reaches its southernmost point in our sky for the year. It occurred 12:04 a.m. Universal Time Sunday, December 21st (6:04 a.m. Central Time). In the illustration, the Earth on the right is at winter solstice.
If you look at a schoolroom globe, you’ll see the Tropic of Capricorn some 23.5 degrees south of the equator. This is where the sun is at zenith – or straight overhead – at noontime today. If you look 23.5 degrees south of the north pole, you’ll see the Arctic Circle. Every place north of the Arctic Circle sees no sun at all today. And every place south of the Antarctic Circle sees the sun all day long. Meanwhile, for the rest of us elsewhere on the globe, today brings the southernmost sunrise and the southernmost sunset of the year. North of the equator, it’s the shortest day and the longest night of the year. South of the equator, it’s the year’s longest day.
